1,2-dichlorohexafluorocyclopentene is an important class of intermediates with high industrial value, which can be used to prepare the etchant of octafluorocyclopentene, the cleaning agent of 1,2,2,3,3,4,4,5-heptafluorocyclopentane, and the like.
Up to now, many documents have reported the methods for preparing 1,2-dichlorohexafluorocyclopentene. Mostly, synthesis is carried out by using hexachlorocyclopentadiene or octachlorocyclopentene as a starting material, wherein the fluridizer used may be SbF5 (see documents U.S. Pat. No. 2,459,783 and Ind. Eng. Chem., 1947, 39 (3), 415-417), SbF3Cl2 (see J. Am. Chem. Soc., 1954, 76 (2), 610-612), SbFxCl5-x (0<x<5) (see J. Am. Chem. Soc., 1945, 67, 1235-1237), or a mixture of SbF3 and SbF1Cl2 (see Journal Indian Chem. Soc., 1953, 30, 525-528). The synthesis may also be carried out by using anhydrous hydrogen fluoride as a fluridizer in the presence of fluorination catalysts such as SbCl5 catalysts (see documents WO9743233, WO9600707 and U.S. Pat. No. 6,218,586) or catalysts containing bismuth or iron (see document U.S. Pat. No. 5,180,861).
The above preparation process has the following disadvantages: first, the starting materials are difficult to obtain; secondly, when the fluridizer is a fluorine-containing and/or chlorine-containing antimony compound, such a fluridizer is highly corrosive and easily hydrolyzed to release hydrogen fluoride or hydrogen chloride gas, which makes it difficult to handle and control in use; when the fluridizer is anhydrous hydrogen fluoride, the fluorination catalyst has low activity and is easily deactivated.